Bernard Madoff’s wife withdrew $10 million from a feeder fund to his securities firm the day before he was busted by the feds, prompting new suspicions she may have been in on his $50 billion scam.

Ruth Madoff also took $5.5 million out of her account at Cohmad Securities Corp. on Nov. 25, about two weeks before her husband’s Dec. 11 confession that his business was “basically, a giant Ponzi scheme.”

The well-timed withdrawals came to light yesterday in a court filing by Massachusetts regulators seeking to revoke Cohmad’s license to operate in the Bay State.

Commonwealth Secretary William Galvin alleged that Cohmad – a Madoff-owned brokerage named after him and co-founder Maurice “Sonny” Cohn – had refused to cooperate in a probe of its role in Madoff’s admitted swindle.

Ruth Madoff’s withdrawals were cited as proof of “Cohmad’s knowledge about flows of funds to and from the Madoff-related accounts,” with Galvin alleging that the two firms are “so intertwined that they could be viewed as a common enterprise.”

Michael Shapiro, a lawyer whose firm represents several Madoff victims, said Ruth’s actions raised “increased suspicion that she was involved on some level” in her husband’s scheme.

Shapiro said the “best-case scenario” for Ruth, a 67-year-old cookbook author, would be if she was just following orders when she extracted the dough.

“If she didn’t know what her husband was up to . . . and didn’t ask any questions, it simply makes her civilly liable and the money recoverable,” he said. “If she did know, she could have criminal exposure herself.”

Shapiro said it was clear the cash was being used to finance Bernard’s defense and the 24-hour security guards that Ruth is paying to guarantee her husband’s house arrest inside their Upper East Side penthouse.

Madoff defense lawyer Ira Sorkin didn’t return a call.

The US Attorney’s Office in Manhattan, which has charged Bernard Madoff with securities fraud, declined to comment.

The judge yesterday extended until March 13 the deadline for an indictment of Bernard, 70, as prosecutors cited ongoing plea negotiations.

Yesterday’s Boston court filing listed a number of questionable transfers between Madoff’s firm and Cohmad.

Regulators said the “limited documents” produced by Cohmad showed that it got more than $67 million from Madoff’s firm for “fees” and “services” between 2000 and last year, accounting for more than 84 percent of its total income.